To evaluate the efficacy, safety, and tolerance of the combination of HIV hyperimmune globulin (administered during pregnancy and to the newborn within 12 hours of birth) and Zidovudine (administered intrapartum and to the newborn for 6 weeks following birth), compared to intravenous immunoglobulin and Zidovudine administered similarly, for the reduction of vertical HIV transmission in HIV-infected pregnant women who are receiving Zidovudine during pregnancy for medical indications.